Rotary hand tool fob cutting plaster casts



June 11, 1929. I F. B. PEDLEY 1.716.66

ROTARY HAND TOOL FOR CUTTIN G PLA STER CASTS Filed Nov. 29, 1926 77-0074 5 Rea/( an or Patented June 11, 1929.

FRANK. B.

ROTARY HAND TOOL non PEDLEY, F POMONA, CALIFORNIA, Assienon onoii'n- VALLEY MACHINE-Worms, "A CORPOfiATION on onniro tniaf ourrriNe'PLiisrnR ciis'rs.

Application ,filed November 1926. Serial No. 151,368. 7 I

As may be inferred from the above title, this invention relates to a hand tool, capable of power operation, particularly designed for use in cutting through plaster casts, such as 5, are employed by surgeons, for the purpose of removing the same. i i 7 It is a general object of my inventioncto provide a rotary grinding or cuttingelement j with'means, preferably disposedin the same plane therewith, for manually advancing said grindingor cutting element, during a power rotation thereof, a a i i It is a further object ot niyinventioi to provide a ban d-supported or hand 7 guided tool, c oinprising a grinding or cutting disc,

with means adaptingthe sameto be operated through a torque or flexible drive,*- such as a protected chain ofjthe general character cur-' rently employed in operating speedometers,

clipping shears,and the like, It is a further ob ect ot my invention to provideia hand tool of the general character.referred to with a housing or main guard and/or with a subsidiary guard,.obviating risk or 11]] ury to an a operative or to a patient from whom a cast is to be removed; and preferred embodiments of my invention may include, in addition to a main housing integral with a handle such as is commonly provided upon a saw orplane,

a substantiallycylindrical bearingboss, disposed centrally of said main housing or guard element. My invention also includes an advantageous arrangement ofbearingjelements, and/or dust excluding elements and/or cutbeing. secured independently of a removable member, such as a slde' plate comprised in the mentioned main housing. i

for patiens, nurses and/or surgeons, it is a main object of my invcntiontoobviate all necessity for the; use of ordinary knives and /or rolling cutters, and all necessity for the insertion. of a wooden ormetallic protecting element, between; a cast and the flesh of a patient, to obviate risk or accidentally cutting said patient, during-the removal of acast;

and preferred embodiments of my invention rate, and withoutrthewslightest physical, or mental distress-tea patient) may comprise means rendering the continuous operation of (all forms thereof being capable of removing casts and wrappings thereon at a very rapid 1 a cutting element contingent upon an application of thumb pressure, or the like, toia conveniently disposedswitch. i Other objects of my invention which ap J pears to be suitable tor numerous uses inadditiontothose'above mentionedmay'be best" I appreciated from the following description an illustrative embodiment of my inven t1on,,tal en in COllllQCtlOIl'Wltll the appended 1 claims and accompanying drawings, inlwhich I I Fig. 1 may be referred to as an elevational ,65 1

v ew, showing an ,embodimentoi' my invention employed in that use for-which saidv invention is primarily'intended,+theremov a1 oft a cast,with its wrjappings,-troina limb. Fig.2 151111 elevational view, comparable with Fig. 1,b'ut drawn to a larger scale, and taken from an opposite direction,ja side plate being removed froina main housing or guard element, td'show'a thin grinding wheel, employed asa rotarycutting'element, there" i Fig. 3 is a transverse sectionalview taken substantially as indicated bythe line.3-'S of Fig. 4- is diagrammatic andintended 1nere-' ly to emphasize the possibility of employing a fine-tooth usual oiispecial saw or a milling u cutter, rather than afgrindingwheel, in air organization of the general character :referredto. v Fig. 5 is a detaili-iew, taken substantiallv .asindicated'by line -5 5 o'fl igfl, to indi cato, on a largenscale, a'preferredtype;of= L V a lmitte-lilre teetlnhsuitable toruseupon a vting-retaining elements,fsome or all or these I tary saw, when usedfor the. purpose of cutting through piaster casts and wrappings of] jcheese cloth, orv therlike,r said teethwpreterably having a backwardinclination.1 The removal of plastercasts having been, 1 at best, a somewhat tedious and'trying ordeal plane With-a disc-like rotaryegrindingor 'cut ting wheel 13..

V The main housingll may;coinprise aree movable side plate; 14, shown as secured by screws l5 over the open end taceot aflpar tially "cylindrical casting 1.5 wliic,h includes also a substantially central; bearing boss 16; lVithinthe latter, I show a shaft-17 as {suplugs 18, 181, respectively; engaging interior shoulders 19: and lS provided by t al 'construction 20, withinsaidbearing boss andv I show said boss as term nallyIprovided with 7 ported byseparate sets of rollers or ball bear r an apertured cap 21, having a central open- 111g 22, sufliolent not only to. receive one end of a flexible'tubular element 23 but to. permit,

the connection of a flexible transmission member, such as a chain 24, extending. there.- through, with a shaft 17,as by a pinning together of coupling element 25and respectively terminating said chain and said shaft. I

There being no very fundamental distinction between a fine-toothed circular saw andi so. interposed: as to. protect the. bearings 18,

18-, an enlargement or expansion 28 may be so disposed on shait 1 7 that, upon the inte POSltlDlh of: fI lCbJOIL washers 29 and or 29,

with or. without. separate metallicoi: other" washers 3O and/or 30, the tightening ot anut or nuts 31, upon a PIIOJQCUDQ' inner end 32-otthe shaft 17, may be relied-upon to h id the.described!cuttingelement, or its erg lent, in an intermediate plane, subri-ztauti.-v I parallel withinnerwalls 3;- 3'3 "pro-:i ded by the housing 11: (or- 11 and plate it.

To the main casting which includes lious inglL andzhandle 12,- or'to either 0 them,

I may secure, asby means oi? scre 34-, a

subsidiary. and removable guard element. such .asa. guar d elemcnt cox-uprising a Flat or. other finger and: anattachment pin dd-these being shown as integrally connect ed by a.webi87,of such restrictedtransyerse' thickness as to enable the-same to advance through a kerzhproducerbbythe rotary cutter 13(or 13 and it; willbe understood that this subsidiary guardelement; may, during; theuse of thedescribed tool in cutting-a cast; from a patients limb, ordinarily rest in con 'tact with theskinof such limb, tending not only to protectthe same from abrasion. by said'motaty; cutter butto guide said cutter,

relatively to tl einner surface of the. cast,

holdingis'aid cntter to its wor-lcg and, assuming-the said rotary cutter'to be operated at a comparatively. high speed (say,e,00.0 to

s 6,000 B: P. M.)- by. means suclias a small electric motor 38,} cur-rentprovided therefore (as, by way of a flexible cord 39, provided with a; connecting plug40) may be controlled. by means such as a foot-open lIBLlfOl manual switch,- included in said circuit and disposed within convenientreachofthe user orn'iy described-toolrasby providing, upon the hair.

' dle12,'o'ritsequivalent; a pressure button all;

a It will be obvious that; for certainuses to. which my novel tool is also appropriate, the

described subsidiary guard comprising finger 35, shown as closely approached by the peripheral edge of the rotary cutter, may be modified or entirely omitted and, although a line-toothed circular saw, or any suitable 7O milling cutter, may be used as a rotary element in;Such'e nbodiineets of my hand tool as may be used in the outlin of wall board orlun iber or metal, in enter to adapt a rotary saw blade to cut: not only through the 7 plaster of a cast but through the liilbllOWYljzlQ- pings thereon, in; so sharpen a rotarysaw; as to form SQPtll'fliQifllt s ..ably separate and backwardly inclined blades fromtheteeth thereoifl thinning the more inclined toiwvard edges of the mentioned tecth, and

rc'erabl-y rotating the resultant cutter in the direction indicated b the 'ous in the cutting oi. 13y Y castings and fabric wrappi-ngs, athin emei. grind ing wheel 13, only a restricted portion of its cutting; edge being exposed beyond t-henicn tioned housing, is found to operate 'w y satisfactorily; but saw-likerotary cutte may be more adyantageous, as 'tcndingtoobx ate clogging, in cutting through moist or slightlypl .'c n ai exact character of} the Let-ta: seiectedj beingdcpendenteither upon the consistcncyot the materialor upon: tie direction of cut. In any event, it will: be obvious that thedes ribed eol iscapablejof very er-qgeditio removing-a c: :t or iinn'r without the sl 'nte'st distress-to a patient or operative ind i t, in case the rotary cutter doesbecome clogged, cleaning may be easily ell ectedby the removal oithe platelet, or its equivalent, without disturbingthe shaft and bezur-ings' V i I The disposition of the handle-l2 in the same plane with the rotary cutteris highly-ad an- 'ageous astacilitatingthe manipulation oi the described tool'wit hone hand, as "in thecase of air-ordinary saw or plane:

Although I haveherein descr-ibeda single and complete embodiment of myinvention disclosing alternative cutting elements, it should be understood-that not: only ar ous-- features thereofmay be independently useel but" alsothat numerous modifications might be made, by those sli'illed inthe new whichsite-ly from said open face; bearingsmount .125

ed in said bearing boss; a shaft:rotatably sup ported by said bearings a disk-like rotary cutting element mounted Qnsaid shaft andadapted to rotate in: the partial cylindrical section of said casting; acoverplate remov- 130- 'oppositely from said open face; bearings mounted in said bearing boss; a shaft rotatably supported by said bearings; a disk-like rotary cutting element mounted on said shaft and adapted to rotate in the partial cylindrical section of said casting; a cover plate removably mounted on said castingjover said open end face and adapted to. provide a housmg for said cutting element; a motorseparate from said tool for imparting rapid'rota tion to said cutting element; flexible driving means interposed between said motor and i said shaft; and, a handle mountedon said housing.

3. A rotary tool for cutting plaster casts which comprises: a partially cylindrical casting having a substantially open end face and providedvvith a bearing boss extending oppositely from said open face; bearings mounted in said bearing boss; a shaft rotatably supported by said bearings; a disk-like rotary cutting element mounted on saidv shaft" and adapted to rotate in the partial cylindrical section of said casting; a cover plate removably mounted on said casting over said open end face and adapted to provide a housing for said cutting element; a motor separate from said tool for imparting rapid rotation to said cutting element; flexible dr1v-' ing means interposed between said motor and said shaft; and a handle mounted on said housing. I

' 4:.A rotary molar cutting plaster casts which comprises: a partially cylindrical casting having a substantially open end face and provided with a bearing boss extending oppositely from said open face bearings mounted in'said bearing boss; a shaft rotatably supported by said bearings; a disk-like rotary'cutting element mounted on said shaft and adapted to rotate in the partial cylin drical'section of said casting; a cover plate removably: mounted on said casting over "said open end face and adapted to provide a housing for said cutting element; ahandle mount ed on said housmg; power means separate from said housmgfor nnpartmg rapld rotation tosaid cutting element; and a guard mounted on" said housing and extendmg therebelo'w. i o

which comprises :a partially cylindrical casting having a substantially open end'face and provided with: a bearing boss extendinglop positely from said open 7 face; bearings. mounted in said bearing boss a shaft rotat-- ably supportedby said bearings; a disk-like rotary cutting element mounted on said shaft and adaptedto rotate in the partial cylin-.

drical section of'said casting; a cover plate removably mountedion said casting over said ed on saidhousing; power meansseparate from said housing for imp'arting rapid rotaopen end face and adapted toprovide a hous 0 mg forsaidcuttmg element; a handle mounttion to said cutting element; and a guard mounted on said housing, provided with an, 1

element which extends intoand is adapted to advance through a kerfcut by said cutting element.

- In testimony whereof I have hereuntoset my hand at Los Angeles, Californiapthis 20th day of November, 1926. a

' FRANK B QPEDLEY v r I 5. A rotary tool for cutting plaster casts 

